It is known that methacrylic acid esters or acrylic acid esters of various alcohols together with hydroperoxides yield mixtures which harden under exclusion of atmospheric oxygen and which can be used as adhesives and sealing compounds. These mixtures, or systems, contain as essential components monomeric or oligomeric (meth)acrylic acid esters of monohydric or polyhydric alcohols, as well as peroxide or hydroperoxide. Accelerators are added to the systems to obtain a sufficiently rigid hardening under exclusion of oxygen.
It is known to use certain sulfur and/or nitrogen-containing organic compounds as accelerators. With these compounds, a strength which permits handling of the cemented objects can be obtained in a relatively short time. Such strength is usually judged according to the so-called hand fastness test, wherein several drops of the anaerobically hardening compound are applied, for example, on the threads of a degreased screw, which is subsequently joined with the respective nut. From time to time the nut is turned slightly toward the screw, and the time is determined until the screw can no longer be turned by hand. This is used as the measure for the hand fastness.
Of greater importance, however, for the use of an anaerobically hardening adhesive or sealing compounds is the time required until the torque of 500 Ncm is necessary to loosen the cemented screw.